Arete TOOLS · TAX PLANNING

IRS Penalty & Interest Calculator

Estimate the cost of late filing and late payment, and see how payments affect your IRS balance.

All tools & calculators

01 · Tax & due dates

Tax year

Income tax return

Unpaid tax at the payment due date ($)After withholding, timely estimated payments, and refundable credits.

Valid filing extension?

Tax payment due date

Return filing due date

02 · Filing & payoff

Date return filed · blank if not filed

Calculate through / payoff date

Assumed future annual interest rate (%)Only used after December 31, 2026. Future rates are projections, not published IRS rates.

03 · Payments credited to tax

Add amounts credited specifically to tax principal after the payment due date. Penalty/interest payments and IRS reallocations are outside this estimate.

04 · Payment plan & levy

Approved installment agreement start

Installment agreement end · blank if ongoing

Notice of intent to levy date

Reduced payment-plan penalties apply only to timely filed individual returns. The levy rate applies to penalty months beginning after the 10-day notice period. Confirm the dates on your IRS notices.

05 · Other assessed penalties

Assessed accuracy-related penalty ($)Enter the actual penalty amount from your notice, not additional tax.

Failure-to-pay penalty already billed ($)Optional amount for penalty-interest estimation only. Already included in the calculated late-payment penalty; not added twice.

Interest start date for that billed penalty

Enter the legally applicable interest start date from your notice/account. Unbilled failure-to-pay penalty interest is excluded.